Expanded pulp article and method of making same



1965 L. HORNBOSTEL, JR 3,201,306

EXPANDED PULP ARTICLE AND METHOD OF MAKING SAME 2 Sheets-Sheet 1 Filed June 11, 1962 p a Z1. M m W w m 1 M m w Jnfl 9 )m H j N M )l d .,\L/ MM/ H .g w .ZP E P mm PREJJl/RE INVENTOR. 1/ 74 firzziasfe fw BY 40 ORNEYS g- 17, 1965 L. HORNBOSTEL, JR 3,201,306

EXPANDED PULP ARTICLE AND METHOD OF MAKING SAME Filed June 11, 1962 2. Sheets-Sheet 2 E I J i? 7. 5

ATTORNEYS United States Patent 3,201,306 EXPANDED PULP ARTIELE AND METHOD 0F MAKING SAME Lloyd Hornbostel, J12, Beloit, Wis, assignor to Beloit Corporation, Beloit, Wis, a corporation of Wisconsin Filed June 11, 1962, Sen No. 201,64% 9 Claims. (Cl. 162-213) The present invention relates to an improved cushioning packaging material and toa method and mechanism for making the cushioning packaging material of which the main component is paper fibers.

An essential feature of protective packaging is low cost and there is need for an inexpensive product for commercial packaging particularly of the type which is disposed of after a single use. Various types of materials have been employed such as polyurethane foam, corrugated paper sections and molded paper pulp. Disadvantages have accompanied materials heretofore used because of high costs and/ or inability of the material to sufficiently absorb impact. Molded pulp is inexpensive but is densely packed and has little resilience, and further requires substantial time for drying in the manufacturing process.

Accordingly, it is an object of the present invention to ,provide a method and mechanism for making protective packaging material which is capable of using inexpensive lwast-e paper pulp, which can be manufactured by uncomplicated relatively lightweight and inexpensive mechanism, and wherein the manufacturing and drying time is small,

so that the mechanism can be used in small production a method and mechanism for making a pulp mat in which the fibers are stacked far apart as compared with a conventionally molded pulp mat and wherein there are substantially less fibers per unit volume as compared with the molded pulp mat.

A feature of the present invention is the provision of a method and mechanism for making a pulp mat for a cushion packaging materially by directing a jet of paper fiber stock against an impingement surface to disperse the stock, permitting the stock to drop freely downwardly after being dispersed against the impingement surface, to a foraminous forming surface, applying a suction beneath the forming surface to hold the mat on the surface, and thereafter evaporating moisture from the mat to dry the layer of pulp.

Other objects, advantages and features of the invention will become more apparent with the teaching of the principles thereof in connection with the disclosure of the preferred embodiments in the specification, claims and drawings, in which:

FIGURE 1 is a schematic side elevational view, shown partly in section, of a mechanism constructed and operating in accordance with the method and principles of the present invention;

FIGURE 2 is a schematic side elevational view of a modified arrangement for drying the pulp mat after it has been formed;

FIGURE 3 is a schematic side elevational view of a 3,201,306 Federated Aug. 31?, lbfifi FIGURE 6 is a perspective view showing the protected tube.

As shown on the drawings:

FIGURE 1 shows a nozzle 10 from which a jet of paper fiber stock is ejected, being supplied to the nozzle through a line if from a pressure stock supply 12.

The stock is formed from a paper fiber pulp and water mixture of at least 2% consistency although a heavier consistency of 5 to 6% operates well in accordance with the principles of the invention.

Refinement of the stock is not necessary and waste stock from Waste paper products provides an inexpensive pulp source. Preparation of the stock is accomplished by mixing with a beater in a batch pulper mechanism such as shown for example in U.S. Patent 2,807,989, Schaan et al., issued October 1, 1957, or in US. Patent 2,954,174, Polleys issued September '27, 1960. The stock is pumped through the supply line 11 to the ejection nozzle which may have an opening on the order of /8 inch. In arrangements requiring larger production a horizontal series of nozzles may be arranged. The stock is forced through the nozzle at a relatively low pressure so that excess spattering does not occur, and a gravity feed is approached, although it will be appreciated that as the stock flows from the nozzle out of the release opening thereof the pressure of the stock is reduced from a relatively higher pressure to a relatively lower pressure.

The stock is emitted from the release opening of the nozzle 10 and engages against an impact or impingement surface 14 of an impact plate 13 which is disposed in a vertical plane so that as the stock is dispersed by striking the surface 14 it is permitted to fall freely downwardly onto a forming surface 16. A housing or hood 15 above the impact plate 13 and behind the nozzle 10 prevents dissipation and loss of the stock into the surrounding air.

As the stock falls freely from the impact plate 13, air is entrained therein and the stock falls down upon the perforated surface of the foramiuous forming surface 16 which has a vacuum below it and the stock forms a mat. The forming surface 16 is positioned above an enclosure or vacuum forming box 17 with a chamber therein being subjected to vacuum by being connected to a vacuum line 19 that is connected to a suitable pump or other means for creating a suction. The forming surface 16 may be provided by any suitable perforate surface and for example a fine porous screen such as used in a Fourdrinier wire is well suited. The forming surface may be stationary and may be moved when a mat of suitable thickness is formed, or it may be arranged to be slowly moving so that a mat of uniform thickness is carried continuously off of the forming box 17. Excessive water of course is received :by the forming box 1-7 and drawn off through the vacuum line 1-9 or through other suitable drain lines.

The formed mat is then dried such as by being carried to an oven 20, preferably remaining on the forming surface, with the mat being shown at M. Within the oven the molded mat is heated such as by electric heating elements 22 and it has been determined that a range of450 to 500 F. is the maximum drying temperature that the stock can withstand without scorching. A /2 inch thick sheet of expanded pulp will dry to 10% bone drying in 30 to 40 minutes under these conditions. When dry the mat is discharged from the oven preferably :at temperatures around 200 F., as indicated by the arrowed line 23, to prevent moisture pick up by the pulp product.

FIGURE 2 illustrates another method of drying the expanded pulp by high velocity air drying hoods 26 and 27. in each of the hoods high velocity drying air is directed into the hoods, and a planar upper drying surface faces the layer of pulp on the forming surface or other support surface 25 and has perforations for the ejection of drying air and other perforations for the removal of moist Q air. This type of arrangement is known per se and need not be shown in detail. With this arrangement, a series of drying hoods 26 may be employed, and the support may be the forming wire continuously moving from the top of a forming box.

In the arrangement of FIGURE 31, stock is supplied from a pressure stock supply 36 such as that described above in connection with FIGURE 1, and the stock flows through a line 31 to be emitted through a nozzle 32 (whereupon it will be apparent the pressure of the stock is reduced) and to be directed in a steam against impact or impingement surface 34 of an impact plate 33. In this arrangement a hood or protective housing 35 extends downwardly below the nozzle and is open in an upward direction with a bafile 3% extending part way over the opening of the housing, extending outwardly from the impact plate 34. The battle prevents the stock from being blown upwardly as it is dispersed by striking the impact surface 34. The dispersed stock will flow upwardly around the end 36a of the battle and up over a Weir 37 formed at the upper edge of the housing 35.

The stock falls freely downwardly through the space S to be deposited on a foraminous forming surface 39. The forming surface is foraminous as described in connection with the arrangement of FIGURE 1, and is positioned above a forming box 38 having a vacuum chamber 40 therein. A vacuum line 41 connects to the forming box and the interior thereof beneath the forming surface 39 is subjected to a vacuum on the order of 1 to 5 inches of mercury. After the mat M forms on the forming surface 39, it is dried by being moved to a drying oven or a drying zone such as described in connection with FIGURE *1 or FIGURE 2.

It will thus be seen that the method makes possible the use of simplified inexpensive lightweight mechanism which may be substantially portable. The arrangement is well adapted to short runs and batch processes. This makes possible the use of the method and mechanism in small installations, and since Waste paper stock can be used, the mechanism can be installed and used by a packaging firm which receives pacakaging materials as waste. When the corrugated packaging materials and other waste papers are received, expanded pulp packaging material can be manufactured on the spot with equipment such as illusfrom a packaging material manufacturer.

The paper fiber mat manufactured in accordance with .the present invention is particularly well suited for the packaging of fragile materials of odd and awkward shapes. Cathode ray tubes as used in television sets and oscilloscopes are particularly hazardous to ship, and surveys show that 20% breakage of television tubes in shipment and handling is not unusual with conventional packaging arrangements.

FIGURES 4 and 5 illustrate a packing construction utilizing the materials of the present invention.

It has heretofore been common practice to use a large number of elements within a corrugated box for packing a television picture tube, and it was necessary to use a combination of soft padded materialplus specially shaped corrugated pads to protect the viewing surface and to use shaped corrugated neck supports for the cathode gun section of the tube. However, molded or corrugated neck supports are somewhat hard and tend to cause shear breakage. 7

With the present arrangement, as illustrated in FIG- URES 4 and 5, the number of packing elements is substantially reduced, and wherein seven individual pieces frequently were used, in the present arrangement only three shock absorbing pieces are employed.

An end cap 47 covers the picture end of the tube 45 within a corrugated box container 46, and the sides of the end cap 47 are turned downwardly as shown in FIG- URE 5. A one inch thick bottom pad 49 with a lower surface adjacent the box bot-tom is coated with a latex coating surface such as of the type known to the trade as Dow 5-12 latex, and this pad supports the cathode ray tube tip and neck bracket. An additional pad 48 is used at the neck to provide a soft contact area thereby avoiding the use of molded or corrugated neck supports which tend to cause shear breakage. The top of the end face cap 47 may also be coated with latex. Longitudin-ally extending tape stringers 50 may be wrapped around the assembly for holding the three packaging pieces 47, 48 and 49 in place for placing into the corrugated box 46, as illustrated in FIGURE 6. Spacers 51 may also be placed between the pads 48 and 49.

The assembled unit has substantially no more weight than arrangements heretofore used and a less expensive superior resilient highly protective support arrangement is achieved. The weight of the cushioning packaging material is slightly less, on the order of 15%, than corrugated material, and is 40% less in weight than conventional molded articles of the same thickness. The strength of the expanded pulp material is equal to that of a vacuum molded pulp article, and yet the product is soft and resilient. The quality of the stock is not critical and a wide variety of waste unrefined pulps may be used as raw stock. High consistency pulps of 5 to 6% may be used where the amount of water to be removed is minimum.

The finished product is well adapted to receiving wet strength resins such as those obtainable commercially and known by the trade names as Kymene 557 and coating such as Dow latex 512 may be used to waterproof the standard pulp article.

Thus it will be seen that I have provided an improved method and apparatus and an improved product made therefrom which meets the objectives and advantages and features above set forth, and is well adapted to a wide variety of applications and uses.

The drawings and specification present a detailed disclosure of the preferred embodiments of the invention, and it is to be understood that the invention is not limited to the specific forms disclosed, but covers all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by the invention.

I claim as my invention:

1. The method of forming a cushioning packaging material which comprises, directing a jet of liquid water mixed paper fiber stock against an impingement surface, permitting the stock to drop freely downwardly solely as a result of gravitational forces to a foraminous forming surface, applying a suction beneath the forming surface to hold the pulp on the forming surface, and drying the pulp.

2. The method of forming a cushioning packaging material which comprises, directing a stream of liquid water mixed paper fiber stock against an impact surface, permitting the stock to drop freely downwardly solely as a result of gravitational forces after being dispersed against said surface to a foraminous forming surface, applying a suction beneath the forming surface, and thereafter drying the layer of pulp on the forming surface.

3. The method of forming a cushioning packaging material which comprises dispersing a mixture of water mixed paper fiber stock by passing it from a higher to a lower pressure simultaneously discharging it horizontally through a release opening, permitting the stock to drop freely downwardly solely as a result of gravitational forces, receiving the dropping stock on a forming surface, and removing moisture from the layer of stock deposited on the surface.

4. The method of forming a cushioning packaging material which comprises directing a stream of water mixed paper fiber stock having a consistency of 5 to 6% of paper fibers in water against an impact surface, permitting the stock to drop freely downwardly solely as a result of gravitational forces after being dispersed against said surface to a foraminous forming surface, applying a suction beneath the forming surface, and thereafter drying the layer of pulp formed on the forming surface.

5. The method of forming a cushioning packaging material which comprises expelling a stream of paper fiber stock at a low pressure against an impingement surface, permitting the stock to drop freely downwardly solely as a result of gravitational forces after being dispersed against said surface to a foraminous forming surface, applying a suction beneath the forming surface, and thereafter drying the layer of pulp formed on the forming surface.

6. The method of forming a cushioning packaging material which comprises, directing a stream of liquid water mixed paper fiber stock against an impact surface, permitting the stock to drop freely downwardly solely as a result of gravitational forces after being dispersed against said surface to a forarninous forming surface, applying a suction beneath the forming surface, and thereafter subjecting the mat formed on said forming surface to a high temperature to evaporate moisture from the mat.

7. The method of forming a cushioning packaging material which comprises, directing a stream of Water mixed paper fiber stock against an impact surface, permitting the stock to drop freely downwardly solely as a result of gravitational forces after being dispersed against said surface to a foraminous forming surface, applying a suction beneath the forming surface, and thereafter subjecting the mat formed on said forming surface to a temperature of 450 to 500 F. to evaporate moisture from the mat.

8. The method of forming a cushioning packaging material which comprises, directing a stream of water mixed paper fiber stock against an impact surface, permitting the stock to drop freely downwardly solely as a result of gravitational forces after being dispersed against said surface to a foraminous forming surface, applying a suction of 10 to 15 inches of mercury beneath the forming surface, and thereafter drying the layer of pulp formed on the forming surface.

9. A cushion pad for packaging comprising a lightweight resilient layer of paper fibers stacked far apart relative to a conventional molded pulp and formed by directing a jet of paper fiber stock against an impingement surface, permitting the stock to drop freely downwardly solely as a result of gravitational forces to a forming surface and removing moisture from the mat formed on the forming surface.

References Cited by the Examiner UNITED STATES PATENTS 1,553,463 9/25 Nishina 162213 1,873,111 8/32 Cannard 162292 2,057,166 10/36 Schur l622l3 2,062,445 12/36 Charlton 162292 2,377,603 6/45 Belden 206-46 2,682,949 7/54 Whitehead 20646 2,919,221 12/59 Labino l62-156 FOREIGN PATENTS 220,992 7/57 Australia.

DONALL H. SYLVESTER, Primary Examiner.

EARLE DRUMMOND, JR., MORRIS O. WOLK,

Examiners. 

1. THE METHOD OF FORMING A CUSHIONING PACKAGING MATERIAL WHICH COMPRISES, DIRECTING A JET OF LIQUID WATER MIXED PAPER FIBER STOCK AGAINST AN IMPINGEMENT SURFACE, PERMITTING THE STOCK TO DROP FREELY DOWNWARDLY SOLELY AS A RESULT OF GRAVITATIONAL FORCES TO A FORAMINOUS FORMING SURFACE, APPLYING A SUCTION BENEATH THE FORMING SURFACE TO HOLD THE PULP ON THE FORMING SURFACE, AND DRYING THE PULP.
 9. A CUSHION PAD FOR PACKAGING COMPRISING A LIGHTWEIGHT RESILIENT LAYER OF PAPER FIBERS STACKED FAR APART RELATIVE TO A CONVENTIONAL MOLDED PULP AND FORMED BY DIRECT- 